1. Field of the Invention
The invention generally relates to AC network interconnections using susceptances, and more specifically to a method of phase-shifting voltages applied to such susceptances, and to a phase-shifting interconnecting apparatus implementing the method to control power transfers between two synchronous polyphase AC networks.
2. Brief Description of the Related Art
Hitherto, phase shifted voltages applied to susceptances of prior AC network interconnecting apparatus are produced by means of phase transposition devices and/or a judicious selection of transformer windings (e.g. combinations of Y-y, Y-d1, Y-y6, etc, -connected windings). Thus, it is possible to provide multiple angles of voltage phase-shifts by step of 30.degree. around a complete 360.degree. range. This method however has the drawback to require a transformer dimensioned to sustain the circulation of the whole power transferred by the interconnecting apparatus.
Moreover, although a continuum of phase-shift angles around 360.degree. can be obtained with partial zigzag combinations of transformer windings for the prior interconnecting apparatus, such topography is not considered in practice for reasons of efficiency.